Abu Dawud said: This tradition has been transmitted by al-Darawardi from "Ubaid Allah on the authority of Ibn "Umar, saying: there was a mu'adhdhin of "Umar, named Mas'ud. He then narrated the rest of the tradition. This version is more correct than one.
In-book : Book 2, Hadith 143
English translation : Book 2, Hadith 533